[RFC/PATCH] Quartz (Mac OS X)

Yet another pull request that continues from #61.

These commits and support for Mac OS X's
Quartz using Core Graphics. It implements
full multimonitor support and the possibility
to test it using RandR. I have only tested it
on GNU/Linux with X using `--enable-fakequartz`.
And I cannot say whether or not it will compile
for or run on Mac OS X or if some porting is
required.